Spill slots cannot alias.

llvm-svn: 84432

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/PseudoSourceValue.cpp b/llvm/lib/CodeGen/PseudoSourceValue.cpp
index 289a52b62a9..70e864050a6 100644
--- a/llvm/lib/CodeGen/PseudoSourceValue.cpp
+++ b/llvm/lib/CodeGen/PseudoSourceValue.cpp
@@ -63,7 +63,7 @@ namespace {
 
     virtual bool isConstant(const MachineFrameInfo *MFI) const;
 
-    virtual bool isAliased() const;
+    virtual bool isAliased(const MachineFrameInfo *MFI) const;
 
     virtual void printCustom(raw_ostream &OS) const {
       OS << "FixedStack" << FI;
@@ -91,7 +91,7 @@ bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
   return false;
 }
 
-bool PseudoSourceValue::isAliased() const {
+bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
   if (this == getStack() ||
       this == getGOT() ||
       this == getConstantPool() ||
@@ -105,9 +105,12 @@ bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
   return MFI && MFI->isImmutableObjectIndex(FI);
 }
 
-bool FixedStackPseudoSourceValue::isAliased() const{
+bool FixedStackPseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
   // Negative frame indices are used for special things that don't
   // appear in LLVM IR. Non-negative indices may be used for things
   // like static allocas.
-  return FI >= 0;
+  if (!MFI)
+    return FI >= 0;
+  // Spill slots should not alias others.
+  return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
 }